Data loading from production to development

I would start by talking with the development manager about how they do
development. I feel the best practice is to clone production back to
development so you get an exact clone. In theory, the developers are
creating stuff that will be implemented on production. Therefore they should
have scripts that can be applied to production, or a clone of production. If
they have made changes and aren't certain what changes they have made, that
doesn't bode well for a smooth implementation.

I feel this development process goes most smoothly when the DBA can
discuss the development process at the beginning of the project and get
agreement on what types of data refreshes, etc. will be needed. Especially
if they have naive ideas about "daily data refreshes" or something.

I would start by trying to understand what they are doing. That said, you
may be backed in a corner here. There are tools that can compare schemas and
help you identify differences. Past that you may just have to slog through
the best way you can. Sounds like you are considering using export/import to
move the data. Fortunately that doesn't require the production database to
be down. Past that you may be looking at some complicated scheme of
materialized views.

And let me guess . . . they want you to have this up and automated by
tomorrow so you can attend to the next crisis -- right?